Do novae hibernate during most of the millenia between eruptions? Links between dwarf and classical novae, and implications for the space densities and evolution of cataclysmic binaries

Abstract

The space densities of classical novae deduced from surveys in the solar neighborhood are about two orders of magnitude lower than those deduced from nova theory and the observed nova outburst frequency in M31. The authors emphasize that there is no observational evidence to support the claim that novae maintain high mass transfer rates more than a century after eruption. They investigate the effects of mass and angular momentum losses during an eruption. For most novae, mass loss dominates, and the separation of the binary stars increases during eruption, as does the Roche radius. It is argued that a nova system by an eruption develops into a detached binary and undergoes a long "hibernation" period with M⪉ 10<SUP>-12</SUP>M_sun;yr<SUP>-1</SUP>. During this phase, gravitational radiation and/or magnetic braking by a stellar wind slowly decrease the separation until Roche lobe contact is restored. The authors predict that most novae spend 90 - 99% of their lives as close but detached red dwarf - white dwarf binaries, photometrically very similar to field main-sequence dwarfs.